Not all of the cards in the DT penalty list are in fact ELO banned.
The -10, -5 and -2 points corresponding with each group represent a penalty that the characters in those groups incur in the DT.
This penalty is incurred when you win a match with a penalty character in your hand, even if you didn't use it. For example, you win a match in which you would usually get 25 points. However if you had Hugo in your hand, you would only receive 15. As I mentioned, this only happens when you win.
I wouldn't recommend using penalty characters in daily tournaments, they generally aren't worth it. You can consider using a -2 character if you have to, but -5 and -10 should be avoided at all costs. They will significantly detriment your scoring, no matter how much they help you win.
Hope this helped.